EP0006617B1 - Toner magnétique - Google Patents

Toner magnétique Download PDF

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Publication number
EP0006617B1
EP0006617B1 EP79102144A EP79102144A EP0006617B1 EP 0006617 B1 EP0006617 B1 EP 0006617B1 EP 79102144 A EP79102144 A EP 79102144A EP 79102144 A EP79102144 A EP 79102144A EP 0006617 B1 EP0006617 B1 EP 0006617B1
Authority
EP
European Patent Office
Prior art keywords
toner
toners
magnetic
resin
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP79102144A
Other languages
German (de)
English (en)
Other versions
EP0006617A2 (fr
EP0006617A3 (en
Inventor
Tsuneaki Kawanishi
Akio Mukoh
Hirosada Morishita
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Proterial Ltd
Original Assignee
Hitachi Metals Ltd
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Filing date
Publication date
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Publication of EP0006617A2 publication Critical patent/EP0006617A2/fr
Publication of EP0006617A3 publication Critical patent/EP0006617A3/xx
Application granted granted Critical
Publication of EP0006617B1 publication Critical patent/EP0006617B1/fr
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/083—Magnetic toner particles
    • G03G9/0837—Structural characteristics of the magnetic components, e.g. shape, crystallographic structure
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0821—Developers with toner particles characterised by physical parameters
    • G03G9/0823—Electric parameters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/083—Magnetic toner particles
    • G03G9/0836—Other physical parameters of the magnetic components
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08726—Polymers of unsaturated acids or derivatives thereof
    • G03G9/08728—Polymers of esters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/104—One component toner
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/105—Polymer in developer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2991—Coated
    • Y10T428/2998—Coated including synthetic resin or polymer

Definitions

  • the present invention relates to a development material for wide use in electrophotographic apparatus, electrostatic recording technique etc., and more particularly to a magnetic toner of the single component type for use, say, in the magnetic brush development process.
  • the present invention relates particularly to transferable magnetic toners.
  • an electrostatic latent image has been formed on a photo conductive plate such as selenium, zinc oxide or the like, which has been electrostatically developed by adding developer particles comprising carrier particles such as glass beads, iron powder or the like and colored micropowder of insulating toner charged by friction, contacting with carrier particles.
  • Such developed image has been directly recorded or transferred by applying a transference sheet thereon and applying electric field.
  • the images transferred on the sheets have been fixed for example by pressure or heat.
  • the copying system which has been conventionally desired is not of a system recording directly on photosensitive paper but of a system recording on normal recording paper or plain paper, i.e., system in which toner particles adhering on a photosensitive body by the development process are transferred to a transferring sheet by contacting the toner particles on the photosensitive body with the transferring sheet and applying electric field.
  • ordinary paper can be used as the transferring sheet and thus has the advantage that copies can be obtained without employing expensive photosensitive paper.
  • styrene acrylic copolymers are known for use in toners.
  • the particles as a whole are insulative, and 0.01 to 10% by weight of hydrophobic silicon is contained.
  • the inventors have found that there arise various problems frequently when images are developed by conventionally known developing processes and transferred from the photosensitive body by employing conventionally known toners and that such problems resulted from the toners being used so that care should be taken in the electric characteristics such as electric conductivity, dielectric constant, etc. of toners and particle size of toners.
  • this invention provides magnetic toner compositions capable to transfer toner images having electric resistivity from 10 9 to 10 16 Ohm.cm at 4000V/cm and a dielectric constant (Eg) from 2.6 to 5 which can transfer well- defined images which have not been obtained by conventional magnetic toner compositions.
  • Fixing procedures of toner compositions include thermal fixing and pressurzation.
  • thermoplastic resins may be usable but should be selected properly depending on thermally fixing procedures, such as heating in an oven, heating by means of hot rolls, etc.
  • Particularly effective and advantageous thermoplastic resins include epoxy resin, acrylate/styrene resin, polyester resin and phenol resin.
  • Such resins are chosen properly depending on the thermal fixing conditions, such as thermal fixing temperature, fixing time, pressure of hot rolls, etc. in view of the softening point, melt viscosity, etc.
  • acrylate/styrene resin and polyester resin are effective.
  • resins having a softening point from 90 to 130°C are effective.
  • Such resins may be used as such or in combination with other compatible resins.
  • Such resins should have a glass transition point of higher than 40°C because of close relation of the glass transition point of the selected resin with the storage stability, fluidity, etc. of the toner compositions. If a resin having a glass transition point of less than 40°C is used, the toner composition tends to agglomerate to make the favorable transference difficult.
  • thermoplastic styrene/acrylate copolymer When it is intended primarily to fix thermally by means of hot rolls, a thermoplastic styrene/acrylate copolymer is used according to this invention.
  • styrene/acrylate copolymers include various types depending on the monomer compositions. As a result of vast.
  • the most suitable resin for magnetic toner compositions comprises (1) at least one monomer selected from the group comprising acrylic and methacrylic acid, (2) styrene and methyl-methacrylate and (3) at least one monomer selected from alkyl acrylates in which the alkyl moiety contains from 1 to 12 carbon atoms and alkyl methacrylates in which the alkyl moiety contains from 1 to 12 carbon atoms.
  • the highly effective transference of toner compositions is made possible without irregular development by using a resin having such a composition to provide transferred images of magnetic toner composition which can be put into practical use.
  • the sole Figure shows a relation between the dielectric constant and transference efficiency of toner compositions.
  • the magnetic toner compositions according to this invention develop favorably conventional photosensitive materials for electrophotography, such as selenium master paper, zinc oxide master paper, organophoto- conductive materials, multilayered composites of various photosensitive materials, etc. by being stuck on a developing magnetic roll to form a magnetic brush.
  • the toner compositions can transfer favorably onto transferring paper by piling together the transferring sheet and applying an electric field thereon.
  • conventional transferring sheets may be employed.
  • transferring sheets having a volume intrinsic resistivity from 10 11 to 10 15 Ohm.cm measured under conditions at 25°C and relative humidity of 70% are preferred. Transferring sheets having a volume intrinsic resistivity from 10 13 to 10 15 Ohm.cm are more preferable.
  • the magnetic toner compositions according to this invention are prepared as follows:
  • Fine magnetic particles include materials very strongly magnetized by a magnetic field to the direction thereof.
  • Examples of such fine magnetic particles include alloys and compounds of ferromagnetic elements such as iron, cobalt, nickel, etc., e.g. ferrite, magnetite, etc. and various alloys, etc. capable to exhibit ferromagnetism by effecting certain treatment such as heat treatment.
  • Such ferromagnetic materials have preferably an average particle size from about 0.1 to about 3 pm for adding them into toner compositions. Desirable amount to be added into a toner composition ranges from 30 to 75% by weight of the total toner composition.
  • the magnetic power will be reduced so that the toner will tend to be released from a developing magnetic roll to disturb the image.
  • the amount beyond 75% by weight will make the milling difficult.
  • fine magnetic particles as such have, in general, electroconductivity, the electric resistivity will be unnecessarily reduced.
  • Color-controlling pigments and dyes may be selected from various ones which have been used conventionally as dry type developers. It is, however, necessary to add such pigments and dyes in a content within the range which does not deteriorate electric characteristics of the toner compositions. In this invention, such an amount is suitably less than 10% by weight of the total toner composition.
  • Usable pigments and dyes include, for example, carbon black, Nigrosine dyes, Aniline Blue, Chalcoil Blue, Chrome Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Lamp Black, Rose Bengal, etc.
  • the fine magnetic particles are inherently colored to an extent that no such color-controlling agent is required, it may be omitted.
  • an improvement may be achieved in the quality of transferred image by using a selected pigment or dye in combination with the fine magnetic particles and a fixing resin for controlling the frictional charge between the toner composition and the surface of developing the magnetic roll or the surface of photosensitive material.
  • a pigment or dye should be added in an amount within the range that the toner composition retains the electrical characteristics as specified in this invention.
  • toner compositions having such components in such proportions are used by pulverizing and classifying or pulverizing, forming into spherules and classifying.
  • the classification may be carried out by means of a classifier, such as Alupine's zigzag classifier. It is desirable to limit the average particle size within the range from 3 to 30 pm. If there are much particles having a particle size of less than 3 ⁇ m, the resulting image will be produced in a high image concentration but markedly fogged. On the other hand if the toner composition contains much particles having a size of larger than 30 ⁇ m, the fogging will be avoided but'the image concentration will be reduced to tend to roughen the image.
  • Classified toner particles may be added with conventional toner additives.
  • Such additives are added for controlling the electric resistivity and fluidity of toner compositions. After the addition of such additives, the electrical characteristics of the resultant toner should fall within the specified ranges.
  • Such additives may be various inorganic or organic materials having an average particle size from 0.01 to 500 ⁇ m. Preferably, such additives are those being effective in an amount from 0.04 to 4% by weight. If such additives are added in an amount less than or more than the above- specified range, the electrical characteristics will fall outside the specified range so that no transference image of high quality will be produced.
  • Such additives which can achieve the present invention include, for example, powdery silica such as aerosil, carbon black, various dyes, metal-containing dyes, micropowder of resins such as polytetrafluoroethylene, styrene, etc.
  • powdery silica such as aerosil
  • carbon black various dyes, metal-containing dyes, micropowder of resins such as polytetrafluoroethylene, styrene, etc.
  • carbon black if added in an amount from 0.1 to 0.4% by weight of the total compositions, has a particularly marked effect for improving the electrical characteristics of the toner and enhancing the development and transference of the toner.
  • the electrical characteristics of the magnetic toner compositions according to this invention depend on types and proportions of materials and the preparing procedures.
  • the electric resistivity is determined by weighing a suitable amount (10 and several mg) of a magnetic toner composition, charging into an insulating polyacetal cylinder which has been measured by a dial gauge as having a diameter of 3.05 mm (sectional area: 0.073 cm 2 ) and measuring the electric resistivity under a load of 1 N in an electric field of 4,000 V/cm, D.C.
  • the dielectric constant is determined by a procedure employing a "Q" meter in which the bottom of a cylindrical cell having an inner diameter of 42 mm is covered with a conductive material to provide an electrode, and the side wall is covered with a polyacetal insulating material having a thickness of 3 mm and a height of 5 mm.
  • the cylindrical cell is charged with 5.0 g of a magnetic toner composition, sandwiched between an opposed pair of disk electrodes of a "Q" meter (available from Yokohama Denki Seisakusho under the trade name of Model QM-102A) and the dielectric constant is measured at a frequency of 100 KHz.
  • thermoplastic styrene/acrylic copolymers are employed as the resin.
  • Such styrene/acrylic copolymers include various copolymers depending on the monomer compositions.
  • the optimum resins for magnetic toners comprise (1) monomer units comprising acrylic acid and methacrylic acid, (2) monomer units comprising styrene and methyl methacrylate and (3) monomer units comprising an alkyl acrylate having 1 to 12 carbon atoms in the alkyl moiety and an alkyl methacrylate having 2 to 12 carbon atoms in the alkyl moiety and contain at least one monomer for each monomer units. That is, to say, by using resins having the above compositions, toner transference free from irregular development and with high efficiency make it possible to obtain transferred magnetic toner images for practical use.
  • the combination and molar ratios selected from each monomer units are selected so that the resulting polymer has glass transition temperature Tg of higher than 50°C, preferably of higher than 65°C, as it is necessary that the glass transition temperature is higher than 50°C, preferably higher than 65°C in order to improve the fluidity and abrasion and wear resistance of the toners.
  • the glass transition temperature is represented in this invention by values as measured by means of Thermomechanical Analyzer Model TMS-1 available from Perkin-Elmer Co.
  • the glass transition temperature of a resin may be calculated from Tg(K) of homopolymer of each monomer so that the Tg'(K) of copolymer may be predicted: wherein Mi is the molar ratio of monomer i, (Tg) ; is the glass transition temperature in K of homopolymer of i monomer and Tg' is the glass transition temperature in K of the copolymer.
  • the combination and molar ratios of monomers selected from monomer units (1) through (3) in this invention are selected so that the Tg value of the copolymer is higher than 50° preferably higher than 65° in the terms of °C.
  • the content of monomer units (2) is less than 20 molar %, the fluidity, printing resistance and wear resistance of the toners will be reduced due to a reduction in the Tg value of the resins. If the content of monomer units (2) exceeds a value of 60 molar %, it is found that the image characteristics, particularly the image density, of the toners are reduced and the image fidelity is also reduced. If the content of monomer units (3) is reduced to a value of less than 20 molar %, it has been found that the image characteristics, particularly the image density, are deteriorated. If the content exceeds a value of 75 molar %, the fluidity, printing resistance and wear resistance have been found to be deteriorated.
  • Monomer units (1) and (2) are called hard monomer components which tend to enhance the glass transition temperature of the resulting copolymers.
  • monomer unit (3) is generally called a soft monomer component which tends to reduce the Tg value of the homopolymers with increasing carbon atoms, thus to reduce the glass transition temperature of the resulting copolymers comprising monomer units (1), (2) and (3).
  • the fixing temperature ranges from 150 to 200°C in conventional copying apparatus.
  • the thermal fixing is better if the softening point of the fixing resins is lower than said fixing temperature.
  • the softening point of a resin may be determined according to the Ball and Ring Method as specified in JIS K-2531.
  • the softening point of a resin depends on its molecular weight, which, in turn, depends on the polymerization conditions for synthesizing the resin.
  • the polymerization conditions for synthesizing the resin.
  • solution polymerization is frequently employed, whose polymerization conditions such as the type and amount of the solvent, catalyst and chain transferring agent, reaction temperature, reaction time, etc. can control the molecular weight of the resulting copolymer.
  • the polymerization conditions are determined so that the softening point of the resulting copolymer is less than the fixing temperature by studying the polymerization conditions to control the molecular weight of the copolymer.
  • the resins according to the invention may be used solely to prepare magnetic toners having good characteristics. However, they may be blended with other resins in order to improve the mechanical and/or temperature characteristics for extending the life of the toners and to improve the fluidity and fixing.
  • Resins to be blended to the resins of the invention include styrene resins, polyvinyl butyral, terpene resins, rosin resins, petroleum resins, epoxy resin, polyamides, wax, ethylene/vinyl acetate copolymer, etc.
  • the ratio of such a resin to be blended depends on the type of the resin but it is important not to exceed a value of 20% by weight as the resin to be blended for preventing deterioration in the developing and transferring characteritics of the toners.
  • the methyl ethyl ketone solution of the resin prepared by such procedure had an NV value (% by weight of non-volatile components) of 60.5% by weight.
  • the solid resin was prepared by removing the methyl ethyl ketone by vacuum drying. The obtained solids had a residue of 98.8% by weight after the heating at 180°C for 30 minutes.
  • the resin When the solid resin was examined by gel permeation chromatography, it was found that the resin had a weight average molecular weight Mw of 38,000, a number average molecular weight Mn of 7,000 and a molecular weight distribution Mw/Mn of 5.4.
  • the resin had a glass transition temperature of 70°C as measured by means of an instrument of Model TMS-1 of Perkin-Elmer Co. and a solftening point of 120°C as measured by the ring and ball method.
  • the resin prepared by this example is termed as No. 61 sample.
  • a magnetic toner was prepared using No. 61 sample as the fixing resin, a magnetite (one available from Toda Kogyo Co. under the trade name of EPT-500) as the magnetic material and carbon black (one available from Mutsubishi Kasei Co. under the trade name of Carbon Black No. 44) as the electroconductive powder.
  • a magnetite one available from Toda Kogyo Co. under the trade name of EPT-500
  • carbon black one available from Mutsubishi Kasei Co. under the trade name of Carbon Black No. 44
  • the resin 35 parts by weight, magnetic powder (60 parts by weight) and carbon black (5 parts by weight) were weighed and premixed for 5 minutes under dry condition in a super mixer.
  • the mixture was then plasticized in a kneader (available from Buss Co. under the trade name of Model TR-46) heated at a temperature from 110 to 120°C.
  • the cooled plasticizer mixture was then crushed through a turbo-mill and the pulverized plastic was added with micronized silica (0.5% by weight, one available from Nippon Aerosil Co. under the trade name of Aerosil R 972) and the mixture was mixed thoroughly.
  • the pulverized mixture was caused to fall down through a heat treating oven heated at a temperature from 200 to 300°C for forming spherules.
  • the toner spherules were then passed through a zigzag classifier to exclude toner particles having a size of less than 3 pm and of higher than 30 pm.
  • the classified toner particles were then added with carbon black (0.1% by weight, No. 44) to prepare a magnetic toner.
  • the electric conductivity was 4 x 10- 13 S.cm- 1 in an electric field of DC 4,000V/cm and the dielectric constant was 3.80 at a frequency of 100 kHz.
  • the toner was then evaluated by its image developed by adhering the toner on a developing magnetic roll having 12 magnetic poles and a magnetomotive force of 6 N (available Hitachi Kinzoku Co.).
  • the development was carried out by mounting the toner and the developing machine on the developing unit of a copying machine (available from Xerox Co. under the name of Model 2200), setting the distance from the photosensitive body to the sleeve of the developing machine at 0.4 mm and rotating the developing magnet roll at 1400 rpm.
  • the toner was electrostatically transferred onto recording paper having an inherent electric volume resistivity of higher than 1014Q. cm as the transferring sheet to prepare a transferred image of the magnetic toner.
  • the transferred image was also fixed by means of a hot recopying roll heated at a temperature from 160 to 200°C.
  • a hot recopying roll heated at a temperature from 160 to 200°C.
  • No. 62 sample of styrene/acrylic copolymer was synthesized from 45 molar % of styrene, 30 molar % of n-butyl methacrylate, 10 molar % of isobutyl methacrylate and 1 5 molar % of acrylic acid similarly to the synthetic example as disclosed hereinbefore.
  • No. 62 sample had a weight average molecular weight Mw of 42,000, a number average molecular weight Mn of 7,000 and a molecular weight distribution Mw/Mn of 6.0. It had a glass transition temperature of 72°C and a softening point of 123°C.
  • a toner was prepared using No. 62 sample in a fully similar manner to that for Example 1 to be evaluated. The results showed that the toner had an electric conductivity of 2.0 x 10 -13 S.cm -1 and a dielectric constant of 4.0 and produced a transferred image of the magnetic toner of high quality and the fixing by means of a hot roll produced no offsetting and an image of high quality.
  • No. 63 sample of styrene/acrylic copolymer was synthesized using monomer mixture comprising 45 molar % of styrene, 40 molar % of isobutyl methacrylate, 10 molar % of acrylic acid and 5 molar % of methacrylic acid similarly to the synthetic example as disclosed hereinbefore.
  • No. 63 sample had a weight average molecular weight Mw of 48,000, a number average molecular weight Mn of 8,000 and a molecular weight distribution Mw/Mn of 6.0. It had a glass transition temperature of 70°C and a softening point of 120°C.
  • a magnetic toner was prepared using No. 63 sample in a fully similar manner to that for Example 1 to be evaluated. The results showed that the toner had an electric conductivity of 5.0 x 10 -13 S.cm -1 and a dielectric constant of 4.15. It produced a transferred image of the toner of high quality and the fixing by means of a hot roll produced no offsetting and an image of high quality.
  • No. 64 sample of styrene/acrylic copolymer was synthesized using a monomer mixture comprising 35 molar % of styrene, 25 molar % of methyl methacrylate, 20 molar % of n-butyl acrylate and 20 molar % of acrylic acid similarly to the synthetic example as disclosed hereinbefore.
  • No. 64 sample had a weight average molecular weight Mw of 49,000, a number average molecular weight Mn of 8,500 and a molecular weight distribution Mw/Mn of 5.76.
  • a magnetic toner was prepared using No. 64 sample in a fully similar manner to that for Example 1 to be evaluated. The results showed that the toner had an electric conductivity of 10 -13 S.cm -1 and a dielectric constant of 4.25. It produced a transferred image of the toner of high quality and the fixing by means of a hot roll produced an image of high quality without offsetting.
  • No. 65 sample of styrene/acrylic copolymer was synthesized using monomer mixture comprising 20 molar % of styrene, 20 molar % of ethyl methacrylate, 55 molar % of n-butyl methacrylate and 5 molar % of methacrylic acid similarly to the synthetic example as disclosed hereinbefore.
  • No. 65 sample had a weight average molecular weight Mw of 40,000, a number average molecular weight Mn of 8,000 and a molecular weight distibution Mw/Mn of 5.0. It had also a glass transition temperature of 65°C and a softening point of 118°C.
  • a magnetic toner was prepared using No. 65 sample in a fully similar manner to that for Example 1 to be evaluated.
  • the toner had an electric conductivity of 8.0 x 10 -13 S.cm -1 and a dielectric constant of 3.95. It produced a transferred image of the toner of high quality and the fixing by means of a hot roll produced an image of high quality free from offsetting.
  • No. 66 sample of styrene/acrylic copolymer was synthesized using monomer mixture comprising 60 molar % of styrene. 20 molar % of n-butyl acrylate and 20 molar % of acrylic acid similarly to the synthetic example as disclosed hereinbefore.
  • No. 66 sample had a weight average molecular weight Mw of 52,000, a number average molecular weight Mn of 7,000 and a molecular weight distribution Mw/Mn of 7.43. It had also a glass transition temperature of 72°C and a softening point of 124°C.
  • a magnetic toner was prepared using No. 66 sample in a fully similar manner to that for Example 1 to be evaluated. The results showed that the toner had an electric conductivity of 10 -14 S.cm -1 and a dielectric constant of 3.60. It produced a transferred image of the toner of high quality and the fixing by means of a hot roll produced an image of high quality free from offsetting.
  • Magnetic toners were prepared using Samples No. 61 through No. 66 of styrene/acrylic copolymers as disclosed in Example Nos. 1 through 6.
  • the toners were prepared similarly to that for Example 11 except that the carbon black was added into the toner sperules in an amount of zero %, 0.05% by weight, 0.5% by weight or 0.6% by weight.
  • the toners containing no carbon black tended to show central fading in solid black areas (i.e., a phenomenon in which the central density of solid black areas is reduced) irrespective of the type of a copolymer samples and showed decreased fluidity.
  • the toners containing 0.6% by weight of carbon black showed high fluidity irrespective of the samples, but tended to be fogged.
  • the toners containing carbon black in an amount of 0.05 or 0.5% by weight showed, however, an electric resistivity ranging from 10- 16 to 10- 9 S.cm- 1 and a dielectric constant ranging from 3.0 to 5.0. They could provide transferred images of the magnetic toners of very high quality and the images could be fixed favourably by means of a hot roll.
  • Transferred images of the magnetic toners employing Sample Nos. 61 through 66 as disclosed in Examples 1 through 6 were produced employing a recopying machine employing photosensitive zinc oxide (available from Sharp Co. under the trade name of Model SF-730) or a recopying machine employing a 2-layered photosensitive body comprising cadmium sulphide an insulating protective layer (available from Canon Co. under the trade name of Model L5) under the same developing conditions as in Example 1.
  • the results showed that the toners produced transferred images of high quality which were fixed favorably by means of a hot roll, irrespective of the type of the toners and recopying machines used.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Developing Agents For Electrophotography (AREA)

Claims (3)

1. Composition pour toner magnétique destinée à développer une image électrostatique latente et effectuer des copies par transfert électrostatique, le toner magnétique comprenant au moins une poudre magnétique et une résine, dont le diamètre des particules est compris dans la gamme de 3 à 30 µm, et dont la résistivité électrique est comprise dans la gamme de 109 à 1016 Qcm à 4000 v/cm en courant continu, et une constante diélectrique comprise dans la gamme de 2, 6 à 5, caractérisée en ce que le composant résineux comprend au moins 80% en poids d'un copolymère de monomères choisis parmi chacun des trois groupes de monomères suivants (1) à (3) représentés par les formules générales:
Figure imgb0009
Figure imgb0010
Figure imgb0011
où R1 est un radical alkyl contenant de 1 à 12 atomes de carbone, et R2 est un radical alkyle contenant de 2 à 12 atomes de carbone; le copolymère contenant au moins un monomère provenant de chaque groupe.
2. Toner magnétique selon la revendication 1, caractérisé en ce que l'on emploie un composant contenant respectivement de 5 à 20% par mole, de 20 à 60% par mole, et de 20 à 75% par mole desdits groupes de monomères (1) à (3).
3. Toner magnétique selon la revendication 2, caractérisé en ce qu'il contient de 0,05 à 0,5% en poids de noir de carbone, sur la base de la quantité de toner.
EP79102144A 1978-06-28 1979-06-27 Toner magnétique Expired EP0006617B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP7744578A JPS556308A (en) 1978-06-28 1978-06-28 Magnetic toner composition for electrostatic transfer
JP77445/78 1978-06-28

Publications (3)

Publication Number Publication Date
EP0006617A2 EP0006617A2 (fr) 1980-01-09
EP0006617A3 EP0006617A3 (en) 1980-01-23
EP0006617B1 true EP0006617B1 (fr) 1983-12-07

Family

ID=13634209

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79102144A Expired EP0006617B1 (fr) 1978-06-28 1979-06-27 Toner magnétique

Country Status (4)

Country Link
US (1) US4265993A (fr)
EP (1) EP0006617B1 (fr)
JP (1) JPS556308A (fr)
DE (1) DE2966463D1 (fr)

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS559531A (en) * 1978-07-07 1980-01-23 Dainippon Ink & Chem Inc Electrophotographic toner which makes possible color copying
JPS5782857A (en) * 1980-11-12 1982-05-24 Olympus Optical Co Ltd Multi-sheet copying method
JPS5797545A (en) * 1980-12-10 1982-06-17 Hitachi Metals Ltd Magnetic toner for electrophotography
JPS5926943B2 (ja) * 1980-12-30 1984-07-02 コニカ株式会社 静電荷像現像用トナ−
JPS58106552A (ja) * 1981-12-21 1983-06-24 Mita Ind Co Ltd 熱定着用の乾式現像トナ−
US4518673A (en) * 1982-04-28 1985-05-21 Hitachi Metals, Ltd. Electrophotographic developer
JPS58189647A (ja) * 1982-04-30 1983-11-05 Mita Ind Co Ltd 二成分系電子写真用現像剤
US4430408A (en) 1982-06-25 1984-02-07 Minnesota Mining And Manufacturing Company Developing powder composition containing a fluorine-modified alkyl siloxane
JPS6076752A (ja) * 1983-10-03 1985-05-01 Sekisui Chem Co Ltd トナ−用樹脂組成物
US4601967A (en) * 1983-12-10 1986-07-22 Ricoh Company, Ltd. Toner particles having a relatively high specific volume resistivity coating layer
JPS62100773A (ja) * 1985-10-29 1987-05-11 Hitachi Metals Ltd 熱ロ−ル定着用現像剤
EP0377553A3 (fr) * 1989-01-05 1991-12-27 Resinall Corporation Composition de développateur contenant une résine acrylique de styrène modifiée de colophane
US5147744A (en) * 1991-02-28 1992-09-15 Xerox Corporation MICR processes with colored encapsulated compositions
EP0658819B1 (fr) * 1993-11-30 2010-06-23 Canon Kabushiki Kaisha Révélateur et agent de développement pour images électrostatiques, procédé pour leur fabrication, et procédé de formation d'images
US5478614A (en) * 1994-10-07 1995-12-26 Minnesota Mining And Manufacturing Company Infrared sensitive recording medium with fluorocarbon surfactant
US5922501A (en) * 1998-12-10 1999-07-13 Xerox Corporation Toner processes
US20060278843A1 (en) * 2003-09-26 2006-12-14 Makoto Someda Spherical composite composition and process for producing spherical composite composition
US8475991B2 (en) * 2009-12-01 2013-07-02 Konica Minolta Business Technologies, Inc. Transparent toner and image forming method
JP6862962B2 (ja) * 2017-03-17 2021-04-21 株式会社リコー 中間転写体、及び画像形成装置

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US2846333A (en) * 1955-11-01 1958-08-05 Haloid Xerox Inc Method of developing electrostatic images
US3563734A (en) * 1964-10-14 1971-02-16 Minnesota Mining & Mfg Electrographic process
US3377286A (en) * 1965-01-19 1968-04-09 Minnesota Mining & Mfg Developer powder containing black magnetic iron oxide
NL159795C (fr) * 1968-07-22 Minnesota Mining & Mfg
US3925219A (en) * 1973-06-29 1975-12-09 Minnesota Mining & Mfg Pressure-fixable developing powder containing a thermoplastic resin and wax
JPS5646596B2 (fr) * 1974-08-28 1981-11-04
JPS5840183B2 (ja) * 1975-01-29 1983-09-03 キヤノン株式会社 静電潜像現像剤
DE2620660A1 (de) * 1975-05-15 1976-12-02 Kip Kk Trockenentwicklerteilchen zur verwendung in der elektrofotografie und verfahren zum entwickeln von elektrostatischen bildern mit solchen teilchen
DE2547118B2 (de) * 1975-10-21 1977-12-08 Elfotec Ag, Zumikon (Schweiz) Verwendung eines magnetischen einkomponententoners in einem verfahren zur elektrophotographischen bildaufzeichnung
DE2559018C2 (de) * 1975-12-29 1983-08-25 Elfotec AG, 8126 Zumikon Verfahren zur Herstellung eines magnetischen Einkomponententoners
JPS5359430A (en) * 1976-06-09 1978-05-29 Konishiroku Photo Ind Co Ltd Electrostatic latent image developer
JPS53103744A (en) * 1977-02-23 1978-09-09 Hitachi Metals Ltd Magnetic toner composite

Also Published As

Publication number Publication date
US4265993A (en) 1981-05-05
JPS556308A (en) 1980-01-17
DE2966463D1 (en) 1984-01-12
EP0006617A2 (fr) 1980-01-09
EP0006617A3 (en) 1980-01-23
JPS574904B2 (fr) 1982-01-28

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